The invention generally relates to an apparatus for scanning a hemisphere in space, and more particularly to an apparatus for using an energy beam and reflected energy receivers to scan a hemisphere in space to detect obstacles to the flight of a helicopter, aircraft, or other vehicle.
The problem of scanning an area for objects at night or in bad weather has long been a problem for all kinds of vehicles. For instance, a helicopter striking obstacles such as wires has been a problem throughout the history of helicopters. Other obstacles can include pylons, radio masts, guy wires, transmission wires, antennas, and cables, and are very serious problems, since many helicopter missions involve flying at low altitudes, or landing in makeshift landing zones. The strategy of  military helicopters is to use the terrain to mask the helicopter from radar or visual detection, and as protection against missile countermeasures. In these missions the crew avoids obstacles by use of visual observation during the daytime and by night vision goggles and thermal imaging systems at nighttime. Deliberately flying low in this manner increases the danger and the need for an obstacle avoidance system such as the invention.
Rotorcraft has the highest accident rate per 100,000 hours of operation of all commercial and military aircraft operated in the US and other countries. Most helicopter crashes occur during landing, often in inclement weather. Because of their vertical takeoff, landing, and hovering capabilities, rotorcraft can operate in a variety of unique and challenging environments not faced by fixed wing aircraft. Pilots often face operational situations where they are unfamiliar with the terrain and environment, and/or operate in inclement weather where visibility is significantly reduced. Combine these issues with above ground electrical wires and power poles, or similar obstacles, and the result can be a main rotor or tail rotor collision with the obstacle.
Several systems have been introduced, such as laser, electromagnetic field detection and radar, but size, weight, area in view, and obstacle size of detection continues to be a challenge for safe operations within these types of environments/conditions. The development and implementation of a cost effective, lightweight, small obstacle detection system with audible and visual warnings when hazards are being approached, within a nearly complete hemisphere of protection, could greatly reduce collisions for rotorcraft in reduced speed operation and landing situations. 
Power transmission lines, cables and wires, which represent the smallest and hardest to distinguish obstacles, are not detectable by conventional radar due to their small size, yet such cables and wire are strong enough to cause a crash of the helicopter. What is needed is a detection system capable of detecting such cables below and around a helicopter, aircraft, or vehicle.
Other needs exist for a scanning array and for scanning using a variety of energy sources, for a number of different purposes. Energy sources can include sound, various forms of laser, radar, microwaves, and other energy types. Such a scanning array would emit energy in beams and include sensors to receive reflected energy. Such an array would be useful to detect collision dangers to helicopters, other aircraft, as well as ground vehicles, and submarines, with the capability of getting each of these vehicle types through physical hazards as well as through rain, dust, and fog.